[B.A.T.M.A.N.] [PATCH] batman-adv: genetlink: make policy common to family

From: Johannes Berg &lt;johannes.berg(a)intel.com&gt; Since maxattr is common, the policy can't really differ sanely, so make it common as well. The only user that did in fact manage to make a non-common policy is taskstats, which has to be really careful about it (since it's still using a common maxattr!). This is no longer supported, but we can fake it using pre_doit. This reduces the size of e.g. nl80211.o (which has lots of commands): text data bss dec hex filename 398745 14323 2240 415308 6564c net/wireless/nl80211.o (before) 397913 14331 2240 414484 65314 net/wireless/nl80211.o (after) -------------------------------- -832 +8 0 -824 Which is obviously just 8 bytes for each command, and an added 8 bytes for the new policy pointer. I'm not sure why the ops list is counted as .text though. Most of the code transformations were done using the following spatch: @ops@ identifier OPS; expression POLICY; @@ struct genl_ops OPS[] = { ..., { - .policy = POLICY, }, ... }; @@ identifier ops.OPS; expression ops.POLICY; identifier fam; expression M; @@ struct genl_family fam = { .ops = OPS, .maxattr = M, + .policy = POLICY, ... }; This also gets rid of devlink_nl_cmd_region_read_dumpit() accessing the cb->data as ops, which we want to change in a later genl patch. Signed-off-by: Johannes Berg &lt;johannes.berg(a)intel.com&gt; Signed-off-by: David S. Miller &lt;davem(a)davemloft.net&gt; [sven(a)narfation.org: Added compat code] Signed-off-by: Sven Eckelmann &lt;sven(a)narfation.org&gt; --- Patch (without compat code) is already in net-next: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/?… compat-include/linux/cache.h | 6 +-- compat-include/net/genetlink.h | 88 ++++++++++++++++++++++++++++++++++ net/batman-adv/netlink.c | 19 +------- 3 files changed, 90 insertions(+), 23 deletions(-) diff --git a/compat-include/linux/cache.h b/compat-include/linux/cache.h index efe440d1..9ddda312 100644 --- a/compat-include/linux/cache.h +++ b/compat-include/linux/cache.h @@ -13,12 +13,8 @@ #include <linux/version.h> #include_next <linux/cache.h> -#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) +#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0) -/* hack for netlink.c which marked the family ops as ro */ -#ifdef __ro_after_init -#undef __ro_after_init -#endif #define __ro_after_init #endif /* < KERNEL_VERSION(4, 6, 0) */ diff --git a/compat-include/net/genetlink.h b/compat-include/net/genetlink.h index 58fc24d7..7d17a705 100644 --- a/compat-include/net/genetlink.h +++ b/compat-include/net/genetlink.h @@ -30,4 +30,92 @@ void batadv_genl_dump_check_consistent(struct netlink_callback *cb, #endif /* < KERNEL_VERSION(4, 15, 0) */ + +#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 2, 0) + +struct batadv_genl_family { + /* data handled by the actual kernel */ + struct genl_family family; + + /* data which has to be copied to family by + * batadv_genl_register_family + */ + unsigned int hdrsize; + char name[GENL_NAMSIZ]; + unsigned int version; + unsigned int maxattr; + const struct nla_policy *policy; + bool netnsok; + int (*pre_doit)(const struct genl_ops *ops, struct sk_buff *skb, + struct genl_info *info); + void (*post_doit)(const struct genl_ops *ops, struct sk_buff *skb, + struct genl_info *info); + const struct genl_ops *ops; + const struct genl_multicast_group *mcgrps; + unsigned int n_ops; + unsigned int n_mcgrps; + struct module *module; + + /* allocated by batadv_genl_register_family and free'd by + * batadv_genl_unregister_family. Used to modify the usually read-only + * ops + */ + struct genl_ops *copy_ops; +}; + +#define genl_family batadv_genl_family + +static inline int batadv_genl_register_family(struct batadv_genl_family *family) +{ + struct genl_ops *ops; + unsigned int i; + + family->family.hdrsize = family->hdrsize; + strncpy(family->family.name, family->name, sizeof(family->family.name)); + family->family.version = family->version; + family->family.maxattr = family->maxattr; + family->family.netnsok = family->netnsok; + family->family.pre_doit = family->pre_doit; + family->family.post_doit = family->post_doit; + family->family.mcgrps = family->mcgrps; + family->family.n_ops = family->n_ops; + family->family.n_mcgrps = family->n_mcgrps; + family->family.module = family->module; + + ops = kmemdup(family->ops, sizeof(*ops) * family->n_ops, GFP_KERNEL); + if (!ops) + return -ENOMEM; + + for (i = 0; i < family->family.n_ops; i++) + ops[i].policy = family->policy; + + family->family.ops = ops; + family->copy_ops = ops; + + return genl_register_family(&family->family); +} + +#define genl_register_family(family) \ + batadv_genl_register_family((family)) + +static inline void +batadv_genl_unregister_family(struct batadv_genl_family *family) +{ + + genl_unregister_family(&family->family); + kfree(family->copy_ops); +} + +#define genl_unregister_family(family) \ + batadv_genl_unregister_family((family)) + +#define genlmsg_put(_skb, _pid, _seq, _family, _flags, _cmd) \ + genlmsg_put(_skb, _pid, _seq, &(_family)->family, _flags, _cmd) + +#define genlmsg_multicast_netns(_family, _net, _skb, _portid, _group, _flags) \ + genlmsg_multicast_netns(&(_family)->family, _net, _skb, _portid, \ + _group, _flags) + +#endif /* < KERNEL_VERSION(5, 2, 0) */ + #endif /* _NET_BATMAN_ADV_COMPAT_NET_GENETLINK_H_ */ diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c index daf56933..e7907308 100644 --- a/net/batman-adv/netlink.c +++ b/net/batman-adv/netlink.c @@ -1344,34 +1344,29 @@ static const struct genl_ops batadv_netlink_ops[] = { { .cmd = BATADV_CMD_GET_MESH, /* can be retrieved by unprivileged users */ - .policy = batadv_netlink_policy, .doit = batadv_netlink_get_mesh, .internal_flags = BATADV_FLAG_NEED_MESH, }, { .cmd = BATADV_CMD_TP_METER, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .doit = batadv_netlink_tp_meter_start, .internal_flags = BATADV_FLAG_NEED_MESH, }, { .cmd = BATADV_CMD_TP_METER_CANCEL, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .doit = batadv_netlink_tp_meter_cancel, .internal_flags = BATADV_FLAG_NEED_MESH, }, { .cmd = BATADV_CMD_GET_ROUTING_ALGOS, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_algo_dump, }, { .cmd = BATADV_CMD_GET_HARDIF, /* can be retrieved by unprivileged users */ - .policy = batadv_netlink_policy, .dumpit = batadv_netlink_dump_hardif, .doit = batadv_netlink_get_hardif, .internal_flags = BATADV_FLAG_NEED_MESH | @@ -1380,68 +1375,57 @@ static const struct genl_ops batadv_netlink_ops[] = { { .cmd = BATADV_CMD_GET_TRANSTABLE_LOCAL, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_tt_local_dump, }, { .cmd = BATADV_CMD_GET_TRANSTABLE_GLOBAL, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_tt_global_dump, }, { .cmd = BATADV_CMD_GET_ORIGINATORS, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_orig_dump, }, { .cmd = BATADV_CMD_GET_NEIGHBORS, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_hardif_neigh_dump, }, { .cmd = BATADV_CMD_GET_GATEWAYS, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_gw_dump, }, { .cmd = BATADV_CMD_GET_BLA_CLAIM, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_bla_claim_dump, }, { .cmd = BATADV_CMD_GET_BLA_BACKBONE, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_bla_backbone_dump, }, { .cmd = BATADV_CMD_GET_DAT_CACHE, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_dat_cache_dump, }, { .cmd = BATADV_CMD_GET_MCAST_FLAGS, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .dumpit = batadv_mcast_flags_dump, }, { .cmd = BATADV_CMD_SET_MESH, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .doit = batadv_netlink_set_mesh, .internal_flags = BATADV_FLAG_NEED_MESH, }, { .cmd = BATADV_CMD_SET_HARDIF, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .doit = batadv_netlink_set_hardif, .internal_flags = BATADV_FLAG_NEED_MESH | BATADV_FLAG_NEED_HARDIF, @@ -1449,7 +1433,6 @@ static const struct genl_ops batadv_netlink_ops[] = { { .cmd = BATADV_CMD_GET_VLAN, /* can be retrieved by unprivileged users */ - .policy = batadv_netlink_policy, .doit = batadv_netlink_get_vlan, .internal_flags = BATADV_FLAG_NEED_MESH | BATADV_FLAG_NEED_VLAN, @@ -1457,7 +1440,6 @@ static const struct genl_ops batadv_netlink_ops[] = { { .cmd = BATADV_CMD_SET_VLAN, .flags = GENL_ADMIN_PERM, - .policy = batadv_netlink_policy, .doit = batadv_netlink_set_vlan, .internal_flags = BATADV_FLAG_NEED_MESH | BATADV_FLAG_NEED_VLAN, @@ -1469,6 +1451,7 @@ struct genl_family batadv_netlink_family __ro_after_init = { .name = BATADV_NL_NAME, .version = 1, .maxattr = BATADV_ATTR_MAX, + .policy = batadv_netlink_policy, .netnsok = true, .pre_doit = batadv_pre_doit, .post_doit = batadv_post_doit, -- 2.20.1